IPAC2014 - List of Authors (Weis, T.)

Paper	Title	Page
MOPRI020	Introducing GunLab – A Compact Test Facility for SRF Photoinjectors	630
SUSPSNE035	use link to see paper's listing under its alternate paper code
	J. Völker, R. Barday, A. Jankowiak, T. Kamps, J. Rudolph, S.G. Schubert, S. Wesch HZB, Berlin, Germany A. Ferrarotto, T. Weis DELTA, Dortmund, Germany V.I. Shvedunov MSU, Moscow, Russia I.Yu. Vladimirov MSU SINP, Moscow, Russia
	Funding: Work supported by German Bundesministerium für Bildung und Forschung (BMBF contract 05K12CB2 PCHB and 05K10PEA), Land Berlin and grants of Helmholtz Association Superconducting radio-frequency photoelectron injectors (SRF photoinjectors) are a promising electron source for high brightness accelerators with high average current and short pulse duration like FELs and ERLs. For the upcoming ERL project BERLinPro we want to test and commission different SRF photoinjectors and examine the beam performance of photocathode materials in an independent test facility. Therefore we designed GunLab to characterize the beam parameters from the SRF photoinjectors in a compact diagnostics beamline. In GunLab we want to investigate the complete 6 dimensional phase space as a function of drive laser and RF setup parameters. In this work we present the design and the estimated performance of GunLab.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI020
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TUPRI043	Analysis of Coupled Bunch Instabilities in BESSY-VSR	1659
	M. Ruprecht, P. Goslawski, A. Jankowiak, M. Ries, A. Schälicke, G. Wüstefeld HZB, Berlin, Germany T. Weis DELTA, Dortmund, Germany
	BESSY-VSR, a scheme where 1.5 ps and 15 ps long bunches (rms) can be stored simultaneously in the BESSY II storage ring has recently been proposed. The strong longitudinal bunch focusing is achieved by superconducting high gradient RF cavities. This paper presents investigations of coupled bunch instabilities driven by HOMs of superconducting multi cell cavities in BESSY-VSR. Analytical calculations and tracking simulations in time domain are performed in the longitudinal and the transverse planes and factors that influence the threshold currents are being discussed. Suitable candidates of cavities which are presently available or in the phase of design are compared with respect to their instability thresholds. G. Wüstefeld, A. Jankowiak, J. Knobloch, M. Ries, Simultaneous Long and Short Electron Bunches in the BESSY II Storage Ring, Proceedings of IPAC2011, San Sebastián, Spain
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WEPRI009	Parameter Studies and Geometry Optimization on Superconducting Multicell RF Cavity Resonators	2496
	B.D. Isbarn, B. Riemann, M. Sommer, T. Weis DELTA, Dortmund, Germany
	Funding: Work partly supported by the BMBF under contract No. 05K13PEB Modern accelerator concepts for high intensity electron beams often require superconducting multicell RF-cavity-resonators in circular accelerators (e.g. storage rings). Caused by strong beam-cavity interaction and due to high quality factors of superconducting RF-structures special care of lower order (LOM) and higher order (HOM) modes must be taken. Various numerical studies were performed to numerically calculate the dependence of different figures of merit (e.g. external quality factors Qext) with respect to the geometry parameters and cell number of the RF-structure, focused on the propagation and damping of low and higher order modes. To ease the numerical effort an optimization routine has been developed which automatically optimizes the geometry based on goal functions. In this context it turned out that cell geometries defined by spline functions have advantages compared to the standard elliptical parametrization regularly used. The number of free parameters is substantially reduced which facilitates the search for optimum solutions.
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Paper

Title

Page

MOPRI020

Introducing GunLab – A Compact Test Facility for SRF Photoinjectors

630

SUSPSNE035

use link to see paper's listing under its alternate paper code

J. Völker, R. Barday, A. Jankowiak, T. Kamps, J. Rudolph, S.G. Schubert, S. Wesch
HZB, Berlin, Germany
A. Ferrarotto, T. Weis
DELTA, Dortmund, Germany
V.I. Shvedunov
MSU, Moscow, Russia
I.Yu. Vladimirov
MSU SINP, Moscow, Russia

Funding: Work supported by German Bundesministerium für Bildung und Forschung (BMBF contract 05K12CB2 PCHB and 05K10PEA), Land Berlin and grants of Helmholtz Association
Superconducting radio-frequency photoelectron injectors (SRF photoinjectors) are a promising electron source for high brightness accelerators with high average current and short pulse duration like FELs and ERLs. For the upcoming ERL project BERLinPro we want to test and commission different SRF photoinjectors and examine the beam performance of photocathode materials in an independent test facility. Therefore we designed GunLab to characterize the beam parameters from the SRF photoinjectors in a compact diagnostics beamline. In GunLab we want to investigate the complete 6 dimensional phase space as a function of drive laser and RF setup parameters. In this work we present the design and the estimated performance of GunLab.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI043

Analysis of Coupled Bunch Instabilities in BESSY-VSR

1659

M. Ruprecht, P. Goslawski, A. Jankowiak, M. Ries, A. Schälicke, G. Wüstefeld
HZB, Berlin, Germany
T. Weis
DELTA, Dortmund, Germany

BESSY-VSR, a scheme where 1.5 ps and 15 ps long bunches (rms) can be stored simultaneously in the BESSY II storage ring has recently been proposed*. The strong longitudinal bunch focusing is achieved by superconducting high gradient RF cavities. This paper presents investigations of coupled bunch instabilities driven by HOMs of superconducting multi cell cavities in BESSY-VSR. Analytical calculations and tracking simulations in time domain are performed in the longitudinal and the transverse planes and factors that influence the threshold currents are being discussed. Suitable candidates of cavities which are presently available or in the phase of design are compared with respect to their instability thresholds.
* G. Wüstefeld, A. Jankowiak, J. Knobloch, M. Ries, Simultaneous Long and Short Electron Bunches in the BESSY II Storage Ring, Proceedings of IPAC2011, San Sebastián, Spain

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI043

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI009

Parameter Studies and Geometry Optimization on Superconducting Multicell RF Cavity Resonators

2496

B.D. Isbarn, B. Riemann, M. Sommer, T. Weis
DELTA, Dortmund, Germany

Funding: Work partly supported by the BMBF under contract No. 05K13PEB
Modern accelerator concepts for high intensity electron beams often require superconducting multicell RF-cavity-resonators in circular accelerators (e.g. storage rings). Caused by strong beam-cavity interaction and due to high quality factors of superconducting RF-structures special care of lower order (LOM) and higher order (HOM) modes must be taken. Various numerical studies were performed to numerically calculate the dependence of different figures of merit (e.g. external quality factors Qext) with respect to the geometry parameters and cell number of the RF-structure, focused on the propagation and damping of low and higher order modes. To ease the numerical effort an optimization routine has been developed which automatically optimizes the geometry based on goal functions. In this context it turned out that cell geometries defined by spline functions have advantages compared to the standard elliptical parametrization regularly used. The number of free parameters is substantially reduced which facilitates the search for optimum solutions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)